OP0251 CLINICAL FEATURES AND TREATMENT-RELATED OUTCOMES OF IGG4-RELATED DISEASE FROM A LARGE EUROPEAN STUDY COHORT
Authors: M. Lanzillotta, K. Overbeek, J. Poulsen, O. Vinge Holmquist, P. Macinga, P. Prescraip Study Group, M. Lohr, J. Rosendahl, E. Della Torre
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> IgG4-related disease is an increasingly recognized systemic fibro-inflammatory disorder involving almost any organ system. Most available data on treatment strategies and natural history of IgG4-RD are currently derived from large cohorts from the United States and Asian Countries. Real-life studies addressing the epidemiology, clinical manifestations, and treatment strategies of IgG4-RD in Europe are limited to smaller cohorts from single center experiences. <h3>Objectives</h3> To characterize the epidemiology, clinical manifestations, and response to treatment of IgG4-RD patients in Europe. <h3>Methods</h3> A pan-European registry (PrescrAIP) was set in place to retrospectively analyse adults diagnosed with IgG4-RD from 2005 and 2020 in 42 European university hospitals. Comprehensive diagnostic criteria and organ-specific criteria were used to diagnose IgG4-RD and central validation was applied. Data on disease epidemiology, clinical characteristics, treatment, and outcomes were retrospectively collected from the hospitals' medical records using a REDCap-based electronic case record form. The IgG4-RD responder index was used to assess response to therapy. Predictors of relapse were identified using multivariable logistic regression analysis after correcting for confounders. <h3>Results</h3> 1079 individuals with suspected IgG4-RD were screened but only 735 were diagnosed with IgG4-RD and considered for analysis (69% male; median age 57years; 85% Caucasian). 45% of patients had multiorgan (&gt;=2) involvement (Table 1). Pancreas, salivary glands, and biliary tree were the most frequently involved organs. Steroid-treatment was started in 634 patients; 9 (1%) were lost to follow-up; 79% (496/625) had a complete response, 18% (111/625) had a partial response, and 3% (18/625) did not respond. 95 patients were not treated; 61% (58/95) had spontaneous complete response, 19% (18/95) had partial response, and 10% (9/95) did not respond. Higher daily steroid dose (&gt;0.4mg/kg prednisone equivalent) was as effective as lower dose (&lt;0.4mg/kg) (OR 0.428; 95%CI 0.054-3.387) for inducing disease response. Similarly, longer induction of remission treatment (&gt; 2 weeks) was as effective as shorter therapy (&lt;2 weeks) (OR 0.908; 95%CI 0.818-1.009). Elevated IgG4 levels were independently associated with a decreased chance of complete response (OR 0.639; 95%CI 0.427-0.955). Relapse occurred in 30% of patients. Relapse within 6 months of remission induction were independent of the steroid tapering duration, induction treatment duration, and total cumulative dose. Parenchymal enlargement (OR 0.390, 95%CI 0.167-0.910) and addition of maintenance therapy with immunosuppressive agents were independently associated with fewer relapses at 6 months (OR 0.299, 95%CI 0.120-0.740). No difference between maintenance therapy with glucocorticoids and rituximab was observed in maintaining disease response. <h3>Conclusion</h3> This is the first pan-European study addressing the epidemiological and clinical features of IgG4-RD in Europe. Our study indicates that patients with elevated IgG4 level may need closer monitoring during remission induction and that 0.4mg/kg/day of prednisone equivalent for at least 2 weeks represents the most effective strategy to induce IgG4-RD remission. <h3>Reference</h3> [1]Lanzillotta M, Vinge-Holmquist O, Overbeek KA, et al. PrescrAIP: A Pan-European Study on Current Treatment Regimens of Auto-Immune Pancreatitis. Front Med(Lausanne). 2020:5;7:408. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.